How incomplete solid-solid contact at the electrode/solid-electrolyte interface drives the interfacial impedance rise that limits solid-state batteries. Distinguishes recoverable contact area (restored by stack pressure) from unrecoverable voids (pressure cannot close them), and shows via electrochemical impedance spectroscopy that non-ideal contact adds a low-frequency interfacial semicircle. Interfacial resistance scales with pressure (about P^-0.5, per contact-resistance theory) and with recoverable contact area (about -1), and distributed contact geometries give lower impedance than concentrated ones due to more uniform potential gradients. Finite-element continuum simulations of the complex potential reproduce the measured spectra. Studied for the Li6PS5Cl argyrodite electrolyte.
This paper isolates and quantifies how contact loss at the electrode/solid-electrolyte interface drives the impedance rise that degrades solid-state batteries, using the argyrodite Li6PS5Cl electroly…